This research characterizes specific epidemiologic and genetic influences upon the decision to seek treatment for alcoholism, and examines the consequences for overall health services use (not limited to alcoholism treatment) of treated versus untreated alcoholism. The project has four aims: (1) specify the excess health services utilization associated with the development of alcohol abuse or dependence; (2) assess the effects upon overall health services utilization of seeking and not seeking professional care for alcohol abuse or dependence; (3) determine other social outcomes (eg. marital breakdown, unemployment, income loss) of treated and untreated alcohol abuse or dependence; and (4) incorporate genetic and environmental sources of variance into models of health services utilization for alcohol abuse or dependence. Aims are addressed by collecting and analyzing pertinent health services utilization data from a genetically informative sample of 2400 fraternal and identical twin pairs drawn from the Vietnam Era Twin (VET) Registry, including 2200 pairs where at least one twin has a history of alcohol dependency or abuse. Aim 1 and part of Aim 3) will be addressed by comparing unaffected and affected twins from MZ and DZ pairs who are discordant for lifetime history of alcoholism. Aim 2 (and part of Aim 3) will be assessed by comparing MZ and DZ pairs who are concordant for history of alcoholism but discordant for receiving treatment, as well as concordant affected pairs who are also concordant for no treatment. Aim 4 will be addressed using all the twins. Because these pairs have already been identified and recently interviewed using the Diagnostic Interview Schedule for another research project, a broad set of relevant demographic, psychiatric, and alcohol and other substance use and dependence data have just become available which supports the proposed investigation. A telephone interview with each twin will collect data updating psychiatric assessments of drug use, alcohol abuse and dependence, and depression, health services utilization for alcohol and non-alcohol related care, and predictors of health services utilization. The telephone interview, conducted by the Institute for Survey Research of Temple University, contractor for data collection on the VET registry since 1987, was chosen because of the national dispersion of the study sample, and the high cost of a face-to-face interview. Data will be analyzed using both epidemiological and biometrical genetic techniques. A twin design addresses the problem of appropriate control group in treatment outcome assessments, and controls for genetic and family environmental contributions to susceptibility to alcohol problems of psychiatric co- morbidity. The use of a population-based twin registry avoids biases associated with ascertaining either on disorder or on treatment utilization, thus maximizing generalizability. Thus a comprehensive analysis of factors influencing health services utilization may be made.